INFLUENCE OF ORALLY-ADMINISTERED EPIDERMAL GROWTH-FACTOR ON NORMAL AND DAMAGED INTESTINAL-MUCOSA IN RATS

The effect of orally administered epidermal growth factor (EGF) on the mucosal growth and hydrolase activity of normal and damaged small int estine was examined in rats. Adult rats fed EGF daily at 10 times the estimated daily intake of EGF from human milk showed increases in spec ific activity but not total activity of various brush-border hydrolase s with unaffected mucosal protein content and villus-to-crypt ratios t hrough day 9. Ingestion of EGF for 13 days resulted in significant dec reases in mucosal protein content without changes in villus height or hydrolase activity. The effect of oral EGF on recovery of damaged inte stine was studied in rats fed a liquid diet supplemented with EGF at 0 , 1, 10, or 20 times the estimated daily intake from human milk after treatment with methotrexate (MTX) to induce acute intestinal injury. A nimals treated with MTX showed significant reductions in body weight a nd small intestinal villus height, mucosal protein content, and hydrol ase activities through day 6 posttreatment. Daily ingestion of EGF did not affect the MTX-induced reductions in mucosal protein content and hydrolase activity by day 3 but caused significant increases in mucosa l disaccharidase and leucine aminopeptidase activity by day 6 at the 1 - or 10-times human milk EGF levels. Similar changes were not observed in MTX-treated rats fed the 20-times human milk level of EGF. These s tudies suggest that oral EGF is capable of modulating mucosal protein levels and stimulating enterocyte hydrolase expression during repair o f the intestinal mucosa.